What are CD-ROM Mode-1, Mode-2 and XA ?

Answer:

The original Yellow Book standard defines two CD-ROM data specification from Red Book by adding two new type of tracks : CD-ROM Mode 1 and CD-ROM Mode 2. These two types are designed to hold computer data, and each data area holds 2352 bytes of data - same as the Red Book's definition but the structure has been redefined.

Afterward the CD-ROM/XA (eXtended Architecture) is further issued from Mode 2 structure. It's basic form is again 2352 bytes per frame/sector, but the structure is different :

Yellow Book definition standardized the CD-ROM data structure, but you will find the application of each of the form as follows :